diff --git a/res/res_smdi.c b/res/res_smdi.c
index ec0b2c4f9d78d1e2fc1127d93d9c68632b45a165..3a8a5f4d6ba9ee019aaf47c9e48433928ce1bfa5 100644
--- a/res/res_smdi.c
+++ b/res/res_smdi.c
@@ -25,6 +25,10 @@
  *
  * Here is a useful mailing list post that describes SMDI protocol details:
  * \ref http://lists.digium.com/pipermail/asterisk-dev/2003-June/000884.html
+ *
+ * \todo This module currently has its own mailbox monitoring thread.  This should
+ * be converted to MWI subscriptions and just let the optional global voicemail
+ * polling thread handle it.
  */
 
 #include "asterisk.h"